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Machine Tool Debugging
will be. Generally, for servo motor systems, the value is between 1000 and 5000; for heavy machine
tools, the value should be smaller. Set the value smaller at the beginning; make the machine tool
perform various typical movements for a period of time, and carefully observe it; if there is no abnormal
situation, increase the value gradually; otherwise, decrease the value and reserve 50% ~ 100%
insurance allowance.
5.5.3. Maximum Speed of Reference Circle
Maximum speed of reference circle corresponds to arc speed limit function. When a machine tool
processes an arc, it will vibrate due to centripetal force. To reduce this kind of vibration, the software
limits machining speed during machining an arc in terms of centripetal acceleration. Take default
setting as an example, the maximum line velocity of the reference circle (Diameter:10mm) is
1800mm/min.
The formula to calculate centripetal acceleration is as following:
2
v
a
r
Among the formula,
(10 / 2)
r
mm
;
1800
/ min
v
mm
;
Thus centripetal acceleration
a
can be calculated; when other arcs are processed, this centripetal
acceleration is the maximum allowable centripetal acceleration. Arc speed will be limited, if it is too
large causing centripetal acceleration larger than
a
calculated in this formula.
5.5.4. Minimum Speed of Reference Circle
Minimum speed of reference circle also corresponds to arc speed limit function.
a
calculated in the
above formula is not the only criterion for arc speed limit function.
2
v
a
r
According to the above formula, in processing an arc with small radius, the line speed will be limited
quite low caused by arc speed limit, which will be a waste of time. Therefore, the software provides the
parameter
―Min. speed of reference circle‖, which is the minimum speed for circular motion. However
small the arc radius is, the machining speed will not be smaller than the value of this parameter.
Usually, given the drive ability of servo motor, frication of machine assembly, and endurance capacity
of mechanical components, the maximum speed of the two axes in actual using can be limited by
modifying the manufacturer parameters
―Max. speed‖ of each axis.